This invention relates to panels adapted to be used in forming interior surfaces of buildings, and is more particularly concerned with large rectangular panels adapted to be held by a framework to form a ceiling.
Structural panels used in forming finished interior walls and ceilings of buildings are generally comprised of gypsum boards, wet felted fibrous boards, slab structures of melt-spun mineral fibers, panels of interadhered wood chips, and other well known materials. The term "finished" is intended to denote a surface which requires either no further treatment or merely a superficial treatment, such as painting, to achieve final form. Ceiling panels, particularly those adapted to be held by a grid-type framework which supports the panels at their peripheral edges, are generally susceptible to sagging, especially when made in large area dimensions such as 2 feet square, or 2 feet by four feet.
Efforts to alleviate the sagging problem by minimizing panel weight have generally led to reduced thermal barrier properties, and have also increased fire risks because the light weight panels are displaced upwardly by pressures or thermal convection currents associated with a fire, thereby facilitating spread of the fire. Embossing techniques have been used to increase the rigidity of light weight ceiling panels. Although such techniques minimize sagging and provide an aesthetically pleasing decorative effect, they have no effect on thermal conductivity through the panel and the lifting of the panel in a fire. When a downwardly disposed surface of a ceiling panel is of a porous nature, as is the case when fibrous materials are used, the surface collects airborne dirt and is non-cleanable.
It is accordingly an object of the present invention to provide a ceiling panel capable of being supported by its peripheral edges without sagging.
It is another object of this invention to provide a ceiling panel as in the foregoing object having improved thermal barrier characteristics.
It is a further object of the present invention to provide a ceiling panel of the aforesaid nature which will resist upward displacement by strong convection currents.
It is still further object of this invention to provide a ceiling tile of the aforesaid nature having a decorative non-porous cleanable downwardly disposed surface.
It is yet another object of the present invention to provide a ceiling panel of the aforesaid nature of rectangular perimeter and adapted to be held by a ceiling-suspended grid-type framework.
These objects and other objects and advantages of the invention will be apparent from the following description.